1. Field of the Invention
This invention relates to a tape guide, and more particularly, to a tape guide in a postage meter type printing machine.
2. Description of the Prior Art
U.S. Pat. No. 3,791,293, assigned to the assignee of the instant invention, discloses a flat-bed printing machine of the postage meter type which can print postage or postage and advertising indicia selectively on letters or on a tape, which in the case of the latter, can be adhered either to an envelope or a parcel. A composite tape is used when the machine is in its tape mode.
This tape comprises a print receiving first strip which has a backing of pressure sensitive adhesive. This strip is divided into units of equal length by perforations defining lines of tear across the tape. A protective second strip is adapted to overlie the adhesive backing of the first strip. The protective second strip extends laterally beyond the first strip along one edge. The extended edge portion of the second strip is slotted with slots or perforations, the midpoints of which, are spaced apart the same distance as the lines of tear in the first strip and are aligned with the lines of tear in the first strip.
The composite tape is threaded through the postage meter printing machine so that an impression can be formed during each print operation on either one or two units of equal length of the first strip of the tape, each unit being defined by the lines of tear across the tape. As the tape is threaded through the postage meter type printing apparatus the tape is advanced from a source of supply such as a tape roll mounted on a first reel, over guide means, a vertically reciprocable track, and at the outer end of the track the protective second strip is separated from the first strip and is led back where its free end is engaged with a second reel which is power-driven to wind up the second strip and thereby advance both strips. The slots or perforations on the extended edge portion of the second strip are placed into meshing engagement with radial projections on a star wheel to rotate the star wheel through a predetermined arc as the tape is advanced. Pins, selectively extended from the rear of the star wheel are used to deactuate the motor driving the take-up reel after either one or two units of the free end of the print-receiving portion of the tape are projected from the machine, with printed indicia thereon.
After each print operation, the free end of the print-receiving strip is projected from one end of the machine and torn off at a line of tear which is disposed adjacent to the point of separation between the two tape strips and also adjacent to the end of the machine. A ramp or inclined tape guide is positioned to contact the free end of the print-receiving strip as it is projected from the machine to deflect it upwardly so it can be readily grasped by the machine operator and torn.
The inclined tape guide includes a pair of spaced, inclined bars which contact the tape along spaced planes.
With the tape threaded through the tape handling apparatus as described above and a postage meter properly assembled with it, a label printing and advancing operation is initiated by the operator depressing a key of the postage meter thus actuating its platen to elevate the tape track bringing the tape which is on the track into contact with a printing head which is within the postage meter.
In falling back to its lower position, the tape supporting track causes actuation of a switch which turns on a motor. The rotation of the motor shaft turns the reel on which the protective second strip is wound up, also unwinding the composite tape from the tape supply reel and advancing it a predetermined distance through the guide means and over the track. The star wheel is rotated by the advancing tape which through its contact pins will deactuate the motor after the print-receiving portion of the tape has advanced either one or two units and is projected and deflected upwardly from the machine.
The inclined tape guide for deflecting the tape includes a pair of spaced, inclined bars, each of which contacts the tape along its adhesive backing layer along spaced planes as it is projected from the machine. It was found that the adhesive backing layer would rub off onto the inclined bars after repeated use of the machine. Subsequent deflection of the imprinted tape units soon became impossible since their adhesive backing would stick to the bars, causing the tape to jam at its exit point from the machine.
In order to alleviate this problem, the print-receiving portion of tape was fabricated so that the adhesive backing layer was not present on the tape along its planes of contact with the inclined deflecting bars. While this solved the jamming problem, it created new problems in the fabrication of the tape since the adhesive backing layer had to be removed or omitted along two parallel planes precisely aligned with the planar surfaces of the deflecting bars which would come into contact with the tape. Accordingly, this solution to the jamming problem was ineffectual.